Hot-air furnace



(No Model.)

2 Sheets-Sheet 1.

J. EVANS.

He'r AIR FURNAGB.

Patented Sept. 9, 1890..

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2 Sheets vSheet 2f (No Model.)

J. EVANS.

HOT AIR PURNAGE.

Patented Sept.

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UNITED lSTATES PATENT OEErcEe JOHN EVANS, OF PHILADELPHIA, PENNSYLVANIA.

HOT-Al R Fu RNACE.

SPECIFICATION forming part of Letters Patent No. 436,075, datedSeptember l9, 1890.

Application filed March 20, 1889. Serial No. 304,075. (No model.)

vuse in starting the fire and an indirect draft from the top of thecombustion-chamber rdownwardly through the furnace and thence tothesmoke-flue, such indirect draft being employed after the fire isstarted and the direct draft is shut off for maintaining a uni- -the useof coal for heating large volumes of cold air.

My invention has for its obj ect simplicity of construction of parts andtheir arrangement so as to increase the efficiency of the furnace, makeit more durable, and to provide for easy access to its component partsforrcleaning or for repairing and replacing thesame.

My invention accordingly consists of the combinations, constructions,and arrangements of parts, as hereinafter described in thespecification, and pointed out in the claims.

Reference is had to the accompanying drawings, wherein- Figure l is avertical section of a furnace embodying my improvements, the coal-chutefor the combustion-chamber being shownv by dotted lines y y; and Fig. 2is a horizontal section of the same on the line l l, Fig. l, the to pplate of the .cold-air chamber being partly broken away and its frontside being partly in section.

A represents the furnace, consisting of the usual outer casing B, theinner casing C, firebox D, combusiionlchamber E, hot-air drum E,direct-draft flue f, having damper f2 and connecting With the smoke-flueH, and coldair chamber G at the bottom of said furnace. The latterconsists of top and bottom plates a a and suitable side and end platesd2 a3, to form an oblong or rectangularshaped coldair chamber, the end gof which extends beyond the-furnace and has a vertical projection grunning up to near the top of the furnace, where it connects with a iiueg2, which leads to the exterior of the building wherein the 4furnace islocated, in order to obtain a supply of fresh or pure air for thefurnace.

The lire-box D may be of any suitable form, having the usual or othergrate and ash-pit. rllhe latter is located in the cold-air chamber inth'e usual manner, as at :10.

The combustion-chamber E may be suitable construction; but I prefer toprovide it with a contracted outlet e, centrally located in its upperend plate e', which is curved outward, as shown, for a purposehereinafter/to be described.

of any e The outlet-pipe e connects with or leads into i V the hot-airdrum F, which has part of its bottom plate inwardly curved,.as at ff',to conform to or correspond with thecurve of the combustion chamber topplate e', so as to profrom the furnace through one or more ofthe l usualcasing-outlets A at the top of the furnace.

Depending from the bottom of drum F are a series of vertically-arrangedpipes f3f4, which extend to. and connect with pipes f6 and f5,respectively, located in the,coldair chamber G. The pipes ff"v runlongitudinally with the cold-air chamber G and are connected by thetransversely-located pipe f6, and f7 is another corresponding pipeconnecting the rear ends of pipes f5 and has at or near its, center aconnection with a pipe f8, which leads up to and connects with thesmoke-flue I-I, said pipe f8 and part of the iiue II being incased inthe vertical cold-air Ioo flue g', as shown more plainly in Fig. l. Thepipes f5, f6, and f7 are separate from, but located and supported in,the cold-air chamber G. The pipe f8 is provided with a suitablylocateddamper fg, which, as shown in Fig. l, is located in said pipe below thedirect-draft pipe f2 or its connection with the smoke-flue H. The pipesf5 are provided with suitablyformed removable covers f1@ for their endsor other parts of the same, and in line therewith on the sides or endsof the cold-airchamber G are openings having doors or removable coversai, by means of which access may be readily had to the said pipes in thecoldair chamber G for cleaning, repairs, replacement, or analogouspurposes.

The operation of. the heater or furnace is as follows: Vhen the fire isto be started, the

. damper f in pipe f8 is closed and damper f2 smoke-flue l-l.

in pipe f is opened, the draft from combustion-chamber E is then throughoutlet c to drum F and through pipe f directly to the smoke-flue H, andsuch draft is the direct draft and is used until the fire is fullystarted, after which the damper f2 is closedto shutoff the direct draftand the damper f is opened. The draft is then from drum F by way of theseries of pipes fsf4 to pipes f5ff7 and from 4the latter throughterminal end or pi pe f s to smoke-flue H, being the indirectdraft-course between the combustion chamber E and The cold-air supplyemerging from ilue q2 passes down flue g in Contact with the pipe f8,absorbing the heat of the hot draft therein, so that said air-supplypasses to cold-air chamber G in a heated condition to be still furtherheated by contact with pipes f5, f6, and f7 before passing through theperforated or skeleton top plate a to the chamber C', wherein is locatedthe fire-box, combustion-chamber, and drum F, and as such air-supplywhen it enters chamber C is well warmed or heated itis economicallyfurther heated by the radiated heat from the combustion-chamber E anddrum the cold-air supply entering Hue g has tocontact with an extendedlength of indirectdraft-flue terminal end f8 and with an extended areaof such Iii1e-pipesf5,f6, and f7, in chamber G, ample time and facilityare provided to admit of such cold air absorbing all structed as abovedescribed, I find that part of the smoke-line H beyond the cold-air flueg2 to be cold, and but one supply of fuel for the furnace per day is allthat is needed to warm or heat suiicient air to thoroughly heat thebuilding wherein the furnace is located 7o for the entire day.

From the foregoing it will be noted that the ash pit or box a: islocated in the coldair chamber G, and the indirect-draft iiues f5 f6 areso located as to embrace or surround 75 the inner sides of the ash-pit,in order to give extended length of radiating-surface to said pipes orilues. Furthermore, the location of said ash-pit and pipes or flues inthe cold-air chamber G admits of a compact form 8o of heater or furnacein height which is suitable for use in the usual restrictedcellarheights of small buildings. i

Vthat I claim isl. In a hot-air furnace, the combination of acombustion-chamber, a cold-air chamber below the level of thecombustion-chamber and having an end extending beyond the furnace, avertical extension or flue from said end leading to the cold-air-inletiiue, a smoke-pipe 9o in said vertical flue leading down to the coldairchamber, an ash pit or box in the coldair chamber, a series of tubularflues in said chamber surrounding or extending around the three sides ofthe ash-pit in said chamber, and flue-connections between thecombustion-chamber and the tubular fines in the cold-air chamber andbetween the latter and the said smoke-fine, substantially as shown anddescribed.

2. In a hot-air furnace, the combination of a combustion-chamber, thesmoke-drum F, cold-air chamber G, below the level of saidcombustion-chamber, having an' outside vertical flue g', an ash-pit, anda series of horizontally-located smoke-fines fifa, and f7 in saidcold-air chamber, said smoke-dues f5, f6, and `f7 being separate fromand extending around the three sides of the ash-pit in chamber G, luesf3, connecting drum F and pipes f5, f, and f7, and a smoke-fine fis,leading from the latter through flue gf, substantially as set forth.

In testimony whereof I aflix my signature in presence of two witnesses.

JOHN EVANS.

Vitnesses:

JOHN RoDGERs, S. J. VAN STAvoREN.

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